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The weak force is best known for its role in nuclear decay. It has very short range but (apart from gravity) is the only force to interact with neutrinos. The weak force is communicated via exchange particles like other subatomic forces. Perhaps the most well known of the exchange particles for the weak force is the W particle which is involved in beta decay. W particles have electric charge – there are both positive and negative W particles – however the Z boson is also an exchange particle for the weak force but does not have any electrical charge. Exchange of a Z boson transfers momentum, spin, and energy, but leaves the interacting particles’ quantum numbers unaffected – charge, flavor, baryon number, lepton number, etc. Because there is no transfer of electrical charge involved, exchange of Z particles is referred to as “neutral” in the phrase “neutral current”. However the word “current” here has nothing to do with electricity – it simply refers to the exchange of the Z particle.

The Z boson can couple to any Standard Model particle, except gluons and photons. However, any interaction between two charged particles that can occur via the exchange of a virtual Z boson can also occur via the exchange of a virtual photon. Unless the interacting particles have energies on the order of the Z boson mass (91 GeV) or higher, the virtual Z boson exchange has an effect of a tiny correction ( (E/MZ)2{\displaystyle ~(E/M_{Z})^{2}~} ) to the amplitude of the electromagnetic process.

Particle accelerators with energies necessary to observe neutral current interactions and to measure the mass of Z boson weren't available until 1983.

On the other hand, Z boson interactions involving neutrinos have distinctive signatures: They provide the only known mechanism for elastic scattering of neutrinos in matter; neutrinos are almost as likely to scatter elastically (via Z boson exchange) as inelastically (via W boson exchange). Weak neutral currents were predicted in 1973 by Abdus Salam, Sheldon Glashow and Steven Weinberg,[1] and confirmed shortly thereafter in 1973, in a neutrino experiment in the Gargamellebubble chamber at CERN.

Fraser, Gordon (3 November 1998). "Twenty-five years of neutral currents". CERN Courier. 27904. Gordon Fraser looks back at how confirmation of the existence of neutral currents ushered in a new understanding of physics.